Brake shoe



1,557,667 M. R. DE FRANCE- BRAKE SHOE Filed-Oct. 16, 1824 2 Sheets-Sheet 1' INVENTOR:

Murr ell R.DeTranc Oct. 20, 1925. 1,557,667

M. R. DE FRANCE BRAKE SHOE Filed Oct. 16, 1924 2 Sheets-Sheet 2 FIB-,

INVENTOR:

I M'urr R DPTTance his afforne Patented Get. 20, 1925.

MURRELL a. nu FRANGE, or BELLEVUE, PENNSYLVANIA.

j l BRAKE Saba.

Application filed October QIG, 1924; Serial: No. ,743,937.

To all whom it may concern:

Be it known thatl, Munnnnn R. De FRANCE, a citizen of the United States, revsiding'at Bellevue, in the county of A110 gheny and State of Pennsylvania, have invented. a new anduseful Improvement inra Brake Shoe, of which the following is a specification.

Tl s invention relates to brake shoes and particularly to, a brake shoe. having a P v pressedsheet metal shell together witha filling of frictional material to be used in exerting a braking effect ronthewheels of railroad cars and similar vehicles;

In such a brake shoe it is entirely the filling of frictional composition whichperforn s the composition filling, inoplace' until the composition is-entirely worn out.

. For a number of years brake shoes of the above type have been manufactured and used, the; shellbeingpressed from a sheetof metal of uniform thicknessthroughout, that is to say the back ends and sides of the shell being of the same thicknessr This shell had one serious defect. JOn long application of the brakes to a railroad car Vgoingdown mountain grades the. sides of the shell Would becomegred hot. Upon the releaseuof the brakes the shell would cool, heat up again on the next applicaton, and this cooling and heating in timeiwould temper the shell to a hardness thatgwould cut or, groove the wheel. This shoe nevercame into general use and 1its -manufacture has been aban- ,doned. 1

An attempt to remedy this defect may be found in patent to Murrell R. De France No. 1,114,343yin which the sides'ofa .pressed brake shoe shell are tapered and corrugated vertically. In such-patent it is stated that ,the metal in the side walls cannot bereduced -.in' thickness throughout their entire heighton account of weakeningthe walls so that they :would not have 'suiiicient strength to hold the frictional compositionof the brake shoe position ,Sinceithe date ofsuch patent, however, it has been discovered how he ableto withstand the thrusts to which small apart the side walls of a shell function in the support of the brake shoedasa whole. NVith the formof'shell shown in such patent, it isffound that as the frictional composition wears away, to expose the tire of a railway car wheel to the thicker portion of the side walls ofthe shell, there is a tendency forjthese walls to heat, temper, and score the rim of thelwheel. Later the-thickness, ofthe sheet of metal the sides'would beeliminated, and the sides of the. shell were reticulatedns in patent to Murrell B. De France No. 1,308,173. This strength torretainthe lug by which the shoe is attached to the hanger, and, because the ends of vthe shell, were. pulled off when the brake shoe became worn down by continued use. Toiremedy these defects the back of the shell was, then corrugated, and an additional reinforcing plate attached to theback,

thus adding; to the cost; of production and assembling, and itzis still a question whether .H

themetal in the sidesgof the shell had been reduced to a ,point where the shoe will meet all classes ofrailroad service without damage tothe wheel.

In the present nvention it is desired to provide a pressed metal brake shoeshell with aback and ends of. comparatively great thickness andistrengt-h, in order that it may it issnbjected without distortion and to preivent the shoe v-from being torn, orthe lug torn loose, when the filling of frictional composition is worn thin. In addition to making; the back and ends of theshell of a strengthsuflicient to prevent the brake shoe from being torn apart it is desired that it be in itself of s-ulficient weight and strength to hold its arc, and consequently the arc-of the brake shoe as a whole, without any supporting effect from the sidesglofthe,shell; If:thebackiandends of a pressedme'tal brake shoe, shell be of the desired strength theisides of the shell maybe asthin as paper, 1.and serve nie-relytto protect the block of frictional composition, forming the fill- (ingniaterial of theibrakeyshoe, from chipping or breaking duringhandling prior to the; attachment ofthe brake shoe to-l a vehicle. Under, such circumstancesthe sides 65 from which the shell is pressed was reduced to a point where it was thought the heating of p 70 lighter weight shell became distorted inuse, because the; back did not have enough button or projection near each end of the shoe. This is to hold the shoe in .alignment with the tread of the wheel.

The lug for receiving the key of the brake shoe hanger must be made separately and attached to the back'of the brake shoe shell.

It is extremely advisable that this lug be so formed as to engage the key of the brake shoe hanger firmly.

If the sheet of metal from which the brake shoe shell is'pressed is heated prior to such operation, the buttons to engage the fingers or guides of the hanger may be pressed out to specified dimensions, no mat ter how thick the back of the shell. They have never, however, been pressed out from a cold sheet to specified dimensions. It is desirable, therefore, to provide a separately formed and attachable button, which may be clinched to the back of the shell, and thus save the cost of heating the sheets. 7

An object of the invention'is topro-v de a brake shoe shell, pressed fro-1n a single 1ntegralcold blank, which has a back of rela tively great thickness and strength togther with sides which are uniformly thin throughout their entire vertical extent.

Another object of the invention is to provide suitable buttons and lug to contact the fingers or guides of the brake shoe hanger and to firmly engage the key thereof.

A still further object of the invention is to provide a pressed brake shoe shell in which 'the'form of the shell provides for the flow and distribution of surplus metal during the operation of pressing the shell.

In the accompanying drawings Figure 1 is a vertical sectional view through the brake shoe of the present invention; Figure 2 1s a bottom plan view thereof; Figure 3 1s a cross sectional view thereof taken on the line 33 Figure 1; Fi ure 4is an end elevationof the brake shoe; Figure 5 is a top plan view of the blank from which the brake shoe is being pressed; Figure 6 is a side elevation of the blank; and Figure 7 is a cross sectional ,view through the blank taken on the line In the drawings the reference numeral 1 designates the brake shoe filling of frictional composition, and 2 the brake shoe shell generally. The filling composition may be of any desired nature, such as a composition offibrous material, coke, and a binder, either with or without a friction increasing material such as metallic borings or filings.

The brake shoe shell proper comprises a back 3, end walls 4, and side walls 5, all of which are pressed into form from a single integral blank 6. r

In the brake shoe of the present invention the blank 6 is a rolled sheet with a central portion 6 of considerably greater thickness than the'side portions, or Webs 6", which extend longitudinally therealong. The back 6 of the blank is punched or cut to provide apertures 7 along the transverse median line of the blank, for the reception of the main lug which receives the brake shoe hanger; and is provided adjacent each extremity of the blank with slots 8 cut or punched for the reception of the end lugs or buttons of the brake shoe.

In forming the brake shoe shell 2, the cold blank 6 is subjected to a suitable die pressing operation. In such operation the longitudinal central portion 6 of the blank becomes theback 3 of the brake shoe shell, while the side or web portions 6" of the bllailik become the sides of the brake shoe s 1e 1.

The end walls 4 of the shell are formed from the areas of the portions 6 of the blank which lie adjacent the extremities thereof. These end walls 4L- must also comprise surplus metal from the side portions 6". In order to permit the flow of this metal from the sides and to distribute the same in the end wall of the shell, and also in order to increase the strength of the end walls, the dies in which the blank is pressed are preferably formed to produce vertical corrugations in the end walls of the shell. This takes up the surplus metal, and saves wear on the necessarily costly dies.

The brake shoe shell 2 thus has its side walls 5 of materially less thickness throughout their entire vertical extent than is the back wall 3 of the shell, thus providing a shell having a strong back and ends, with sides which comprise a minimum quantity of metal.

The main lug 9 for receiving and engaglng the key of the brake shoe hanger is se cured to the shell prior to the pressing of the filling of frictional composition thereinto, by extending the extremities of the side walls, or tongues of the lug downwardly through the slots 7 in the back of the shell and bending upwardly the portions of these tongues or sides which project into the body of the shell. In order that it may grip and firmly engage the key of a brake shoe type of shoe.

hanger, this lug isshown asprovided with sharp teeth .or protuberances 9 on the under surface of thetop portion of the lug. As shown inFigure 9; of the: drawings, these teeth 9 may be initially formed as ridges in punching the blank 9? for. the lug by slightly upsettingia small amount of metal along the side edgesof the blank, as in the regions 9?. The final operation of pressing'the lug then converts theseupset regions into; the teeth 9 of the lug. i

lVith brake shoe shells pressed from sheet metal,the .cndl-ugs, or buttons, of the brake shoe have previously been provided by slotting the back of-the shelliadjacent the extremities thereof, or heating the blank, and pressing out upwardly extending tongues, which receive a filling of the frictional composition in pressing the same into the shell, to form buttons. Since, however, the present integral shell comprises no reinforcement for its back, it is desirable to Weaken the back as little as possible. For this reason as well as for reasons of manufacturing expediency, the slots 8 are provided, and simple lugs 10 are secured to the back of the shell by means of tongues 10, which extend downwardly through the slots and are bent upwardly against the inner surface of the back 3.

The brake shoe of the present invention approximates the simplicity of manufacture, and all the specified dimensions, of a cast brake shoe, while retaining all the advantages of cheaper production cost incident to the pressed shell and filling composition The thickness of the back wall of the brake shoe shell, and the relative thinness of the side walls throughout their entire vertical extent, give a maximum of resistance to breaking or distortion of the shoe during any stage of its gradual wearing away in use, while presenting a minimum of sheet metals to the tire of a wheel with which the brake shoe is used.

The relatively great thickness, and the corrugated form of the end walls of the shell also assist materially in supporting the back and assisting to maintain the arc of the brake shoe.

What I claim is:

1. In a brake shoe having a filling of composition, a containing plate having a thick central portion extending substantially the length thereof and thinner side portions along the edges thereof, said plate being pressed to form a dish shaped container the ends of which are corrugated vertically to take up surplus metal of the plate.

2. In a brake shoe having a filling of composition, a containing plate having a thick central portion extending substantially the length thereof and thinner side portions along the edges thereof, said plate being pressed to provide a dish shaped container the relatively thin :sides of which are formed pressed to provide a dish shaped container the relatively thin sides of which are formed by bending theplates along the lines formed by the change of thicknessin the plate, and the ends of which are corrugated vertically to takejup surplus metal of. the plate.

4. In a brake shoe having a filling of composition and a pressed metal shell embracing the same, a metallic shell pressed from a single integral blank whichhas a relatively thick back wall and relatively thin side walls of uniform thickness throughout their vertical extent, and a separately formed lug attached to the back of the shell and having in the key way thereof teeth for firmly engaging the key which connects the brake shoe to its hanger.

5. In a brake shoe having a filling of composition and a pressed metal shell embracing the same, a metallic shell pressed from a single integral blank which has relatively thick back and end walls and relative-- ly thin side walls of uniform thickness throughout their vertical extent, and a separately formed lug attached to the back of the shell and having in the key way there-of teeth for firmly engaging the key which connects the brake shoe to its hanger.

6. In a brake shoe having a filling of composition and a pressed metal shell embracing the same, a metallic shell pressed from a single integral blank which has relatively thick back and end walls and relatively thin side walls of uniform thickness throughout their vertical extent, the end Walls of the shell being corrugated vertically thereof and a separately formed lug attached to the back of the shell and having in the key way thereof teeth for firmly engaging the key which connects the brake shoe to its hanger.

7. In a brake shoe having a filling of composition and a pressed metal shell embracing the same, a metallic shell pressed from a single integral blank which has a relatively thick back wall and relatively thin side walls of uniform thickness throughout their vertical extent, separately formed end lugs or buttons for contacting the fingers of a brake shoe hanger attached to the back wall of the shell, and a separately formed lug attached 'to the back of the shell and having in the key way thereof teeth for firmly engaging 1 the key which connects the brake shoe to its hanger.

8. In a brake shoe having a filling of com position and a pressed'metal shell embracing the same, a lug for receiving the key of a brake shoe hanger formed separately from the shell and adapted to be attached to the back thereof, said lug having in the key Way thereof teeth for firmly engaging the key which connects the brake shoe to its hanger.

9. In a brake shoe having a filling of composition and a pressed metal containing shell embracing the same, a metallic shell pressed from a single integral blank which has a relatively thick back and relatively thin sides of uniform thickness throughout their entire vertical extent, the change in thickness between said back and sides being abrupt along the lines of change of direction between the back and sides.

10. In a brake shoe having a filling of composition and a pressed metal containing shell embracing the same, a metallic shell pressed from a single integral blank which has a relatively thick back and relatively thin sides of uniform thickness throughout their entire vertical extent, the change in thickness between said back and sides being abrupt and along the lines of change of direction'between the back and'sides, and the ends being corrugated vertically to take up surplus metal in pressing. In witness whereof, 'I

hereunto set my hand.

MURRELL R. DE FRANCE. 

